ON Semi has confirmed that there is no difference between these two part numbers. ON Semiconductor acquired Fairchild Semiconductor on September 19th, 2016. The FSA2567UMX-F135 is a former Fairchild part and Fairchild used this -F135 suffix as an internal description for enhanced EMI option for this part. The FSA2567UMX and FSA2567UMX-F135 can be used interchangeably.
Please note that the FSA2567UMX-F135 is obsolete. The FSA2567UMX is active and recommended for new designs.
Applicable part numbers